we have a renewed chance to speculate about a follow-up to Deus Ex: Human Revolution

Thank GOD! Now get this Thief bidness out the door and get back to DX.

Different teams. The DX:HR team was actually working on the multiplayer for TR. Why they were working on that instead of the next DX? Nobody knows. It's possible that the next DX was still in pre-production so they needed something else for the bulk of the team to do.